DHCP+SUPERSCOPE+VLAN=NACK

Setup-Windows 2003 Standard Edition Domain Controller holding FSMO
roles running DHCP, DNS, and WINS.

The Microsoft propaganda that I've come across suggests that DHCP
Superscopes are best utilized when you have several logical networks
running across the same physical segment.

I.e. if you have 5 VLans running on one wire- it becomes appropriate to
utilize superscopes.
So here is the problem I'm having. The layer 3 router which routes
between the VLans is appropriately setup. We are utilizing the DHCP
helper command in the router to forward all DHCP requests to our
server. This seems to work fine *most* of the time. Spontaneously a
few systems seem to get stuck in this rut of being unable to contact
the DHCP server. The DHCP server shows a NACK in the log file. The
resolution has been to delete the lease on the DHCP server and change
the VLAN of the port that the system is connected to. This has been
the only way to solve this problem.

Alternatively we removed the affected scope from the superscope and the
problem goes away. Why are we having this problem if the scope is
contained in the Superscope? Why would the DHCP server be sending a
NACK on the VLAN? Isn't this the point of a superscope? Is it
necessary to use the Superscopes? What's the freaking point of a
superscope? Why if we have 7 subnets /VLans only one or two are
affected? Why if we have 400 pcs only 20-30 affected? Why doesn't
Microsoft have better logging capabilities on DHCP Server? Why won't
Bill Gates loan me $100,000?

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Setup-Windows 2003 Standard Edition Domain Controller holding FSMO
> roles running DHCP, DNS, and WINS.
>
> The Microsoft propaganda that I've come across suggests that DHCP
> Superscopes are best utilized when you have several logical networks
> running across the same physical segment.
>
> I.e. if you have 5 VLans running on one wire- it becomes appropriate to
> utilize superscopes.

There are not talking about VLANs, they are talking about Multi-Netting.
VLANs are on different "logical wires" which behaves the same way as
different "physical wires" as far as DHCP is concerned.

Multi-Netting is when you run more than one IP Segment on the same physical
wire *without* doing VLANs. It is rarely done anymore,...in fact,..in my
opinion,..the invention of VLANs eliminated the need for Multi-Netting for
the most part.

Get rid of the SuperScopes. Use separate individual regular Scopes.

--
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
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Understanding the ISA 2004 Access Rule Processing
http://www.isaserver.org/articles/IS...cessRules.html

Microsoft Internet Security & Acceleration Server: Guidance
http://www.microsoft.com/isaserver/t...dance/2004.asp
http://www.microsoft.com/isaserver/t...dance/2000.asp

Microsoft Internet Security & Acceleration Server: Partners
http://www.microsoft.com/isaserver/partners/default.asp

Deployment Guidelines for ISA Server 2004 Enterprise Edition
http://www.microsoft.com/technet/pro...isaserver.mspx
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